How come people in the 1700's and 1800's that believed in scientific racism used such hilarious and silly explanations to describe races?

Carl Linnaeus (1707–1778), the Swedish physician, botanist, and zoologist, he made these claims about races The Americanus: red, choleraic, righteous; black, straight, thick hair; stubborn, zealous, free; painting himself with red lines, and regulated by customs. The Europeanus: white, sanguine, browny; with... show more Carl Linnaeus (1707–1778), the Swedish physician, botanist, and zoologist, he made these claims about races

The Americanus: red, choleraic, righteous; black, straight, thick hair; stubborn, zealous, free; painting himself with red lines, and regulated by customs.

The Europeanus: white, sanguine, browny; with abundant, long hair; blue eyes; gentle, acute, inventive; covered with close vestments; and governed by laws.[20]

The Asiaticus: yellow, melancholic, stiff; black hair, dark eyes; severe, haughty, greedy; covered with loose clothing; and ruled by opinions.

The Afer or Africanus: black, phlegmatic, relaxed; black, frizzled hair; silky skin, flat nose, tumid lips; females without shame; mammary glands give milk abundantly; crafty, sly, lazy, cunning, lustful, careless; anoints himself with grease; and governed by caprice
Update: 2 scientist from the 1700 and 1800's claimed, *****..id pigmentation arose because of the heat of the tropical sun. They suggested cold wind caused the tawny colour of the Eskimos. They thought the Chinese relatively fair skinned compared to the other Asian stocks because they kept mostly in towns and were... show more 2 scientist from the 1700 and 1800's claimed, *****..id pigmentation arose because of the heat of the tropical sun. They suggested cold wind caused the tawny colour of the Eskimos. They thought the Chinese relatively fair skinned compared to the other Asian stocks because they kept mostly in towns and were protected from environmental factors. Buffon said that food and the mode of living could make races degenerate and differentiate them from the original Caucasian race
Update 2: Benjamin Rush (1745–1813), a Founding Father of the United States and a physician, proposed that being black was a hereditary skin disease, which he called "negr....o..idism", and that it could be cured. Rush believed non-whites were really white underneath but they were stricken with a non-contagious... show more Benjamin Rush (1745–1813), a Founding Father of the United States and a physician, proposed that being black was a hereditary skin disease, which he called "negr....o..idism", and that it could be cured. Rush believed non-whites were really white underneath but they were stricken with a non-contagious form of leprosy which darkened their skin color
Update 3: another scientist by the name of meiners said

the ne...gro felt less pain than any other race and lacked in emotions. Meiners wrote that the Ne....gro had thick nerves and thus was not sensitive like the other races. He went as far as to say that the ***** has "no human, barely any animal, feeling".
Update 4: Meiners wrote that the noblest race was the Celts. They were able to conquer various parts of the world, they were more sensitive to heat and cold, and their delicacy is shown by the way they are selective about what they eat.
Update 5: Meiners claimed that Slavs are an inferior race, "less sensitive and content with eating rough food". He described stories of Slavs allegedly eating poisonous fungi without coming to any harm. He claimed that their medical techniques were also backward: he used as an example their heating sick people in... show more Meiners claimed that Slavs are an inferior race, "less sensitive and content with eating rough food". He described stories of Slavs allegedly eating poisonous fungi without coming to any harm. He claimed that their medical techniques were also backward: he used as an example their heating sick people in ovens, then making them roll in the snow.[36].
Update 6: this stuff is incredibly archaic and racist.

but I admit that its hilarious in the way they describe people LOL

and I'm not even white and take zero offense to it
Update 7: natives are stubborn, zealous and paint himself with red lines?? LOL asians are haughty, yellow, greedy, melancholic with loose clothings?? LOL europeans are governed by laws, inventive, sanguine, abundant?? LOL blacks are relaxed, frizzy, lazy, females without shame?? glands that give milk abundantly?... show more natives are stubborn, zealous and paint himself with red lines?? LOL

asians are haughty, yellow, greedy, melancholic with loose clothings?? LOL

europeans are governed by laws, inventive, sanguine, abundant?? LOL

blacks are relaxed, frizzy, lazy, females without shame?? glands that give milk abundantly? lustful? LMAO WTF???? HAHAH
Update 8: I know this is incredibly archaic, but can you at least agree this is a bit humorous??? LMAO 
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